Rather than batons or rubber bullets, some police departments have started using an intense beam of sound to manage protesters, but the annoying tone has drawn criticism from some who say it can cause permanent damage.
More U.S. police and emergency-response agencies are using the so-called Long-Range Acoustic Devices instead of megaphones or conventional loudspeakers for crowd control. The leading manufacturer, LRAD Corp. of San Diego, said the product was developed as a nonlethal option for military use.
Some people who have been on the receiving end call the devices "sound cannons." A woman is suing the city of Pittsburgh claiming the piercing tone from a police blaster during the 2009 G-20 summit permanently damaged her hearing. There were reports that New York City police used the punishing tone on protesters, though the department said it used the device only to broadcast messages.
LRAD (pronounced L-rad) said its products offer police something louder than a megaphone and more benign than rubber bullets and tear gas for managing crowds, defusing hostage situations and communicating at from a safe distance with dangerous suspects.
"All of these events have helped bring interest to LRAD as new way to take care of these type of situations where they haven't had them before," company spokesman Robert Putnam said.
He said LRAD is not a weapon but a long-range communication system for clearly broadcasting information, instructions and warnings.
The publicly traded company had record sales of $26 million in the 2011 fiscal year ending Sept. 30, up 57 percent from a year earlier. Foreign and domestic military customers accounted for at least 58 percent of sales.
The company said Dec. 5 in its year-end report that it sees increased applications for LRADs in areas including law enforcement.
The devices were developed for the U.S. Navy after the deadly attack in 2000 on the USS Cole off Yemen in to give sailors a way of ordering small boats approaching U.S. warships. They have also been used to deter pirates from attacking cruise ships and communicating with Hurricane Katrina victims in 2005.
The products range from a 15-pound, battery-operated, hand-held unit to a 320-pound device with a range of nearly 2 miles. Even the smallest unit, the LRAD 100X, emits as much as 137 decibels at 1 meter, which is louder than a jet takeoff at 100 meters. The sound is still slightly lower than the pain threshold of 140 decibels, according to the U.S. Occupational Safety and Health Administration.
Putnam said broadcast levels are purposely kept below the threshold that could cause permanent hearing damage from brief exposure. He said hearing it over a longer period of time would cause damage, the same way a fire siren over an extended time would hurt.
The sound at close range causes most people discomfort, and they cover their ears and move away, he said.
An Associated Press reporter witnessed a demonstration in September of the 149-decibel, 500X model at Marine Corps Base Quantico, in the northern Virginia suburbs of Washington. At a distance of about 250 yards, it clearly emitted spoken words, a recorded train whistle and an irritating squeal - the alert tone - similar to a car-theft alarm.
Karen Piper knows what the squeal sounds like. The University of Missouri English professor was visiting Pittsburgh during the September 2009 G-20 summit to research whether protesters have any effect on the International Monetary Fund and World Bank. She claims in a lawsuit she was about 100 feet from an LRAD mounted on a moving vehicle when it bombarded her with a "piercing, continuous, high-pitched sound" for minutes, causing permanent hearing loss.
The American Civil Liberties Union is representing Piper in her lawsuit against the city, claiming violations of her constitutional rights of assembly, privacy and due process. The complaint, filed in September, alleges the city was negligent, reckless and careless. Piper "was forced to endure great pain, suffering and inconvenience," the complaint said.
The city said the sound blaster was used according to the manufacturers' safety instructions.
Piper, 46, said in an interview that the high-frequency hearing loss she suffered makes it hard for her to distinguish among certain consonants.
"I have trouble hearing in restaurants, and I have trouble making out sounds when there's background sounds," she said.
Putnam said that if Piper was 100 feet away, the loudest sound she could have encountered would have been about 120 decibels - lower than emergency sirens or custom car stereos. And he said if the blaster was moving, the exposure would have been seconds, not minutes.
Exposure to a sound of 120 decibels should not equal or exceed 9 seconds, according to the National Institute for Occupational Safety and Health says e.
Raymond DeMichiei, deputy director of the Pittsburgh Office of Emergency Management and Homeland Security, said he's never seen a better device for communicating with an unruly crowd.
"What would you rather have us do, the old 1964 routine with fire hoses and billy clubs? I think it's a lot more humane to make people uncomfortable because their ears hurt, and they leave," he said.